The present invention relates to improvements in foldable spectacle frames.
It is disclosed U.S. Pat. No. 4,820,035 one type of spectacle frame comprising lens frames and temples, wherein the temples are foldable to a thin form in substantially the same plane as the lens frames without lapping over the lens frames, such as shown in FIG. 8.
As shown in FIG. 8, the opposed temples, indicated as 306 and 306a, each comprises an auxiliary temple member 303 and a main temple member 304. The auxiliary temple member 303 which has a length corresponding to a vertical width of the lens frame 301, is supported by an outer portion of upper side 310 of the lens frame and is movable about a pivot 331. in an auxiliary plane of pivotal movement substantially orthogonal to the plane of the lens frame 301. The main temple member 304 is pivoted at a pivot 337 to the auxiliary temple member 303 and movable about the pivot 337 in a main plane of pivotal movement that is orthogonal to the auxiliary plane of pivotal movement of the auxiliary temple member 303.
The auxiliary temple members 303 and the main temple members 304 of the above spectacle frame can be located substantially in the same plane as the lens frames after folding. Accordingly, the spectacle frame has advantage of being foldable to a thickness smaller than common spectacle frames having temples which lap over the lens frames when folded.
With the spectacle frame described, the auxiliary temple member 303 is biased in an unfolding direction by a torsion spring at a location that the auxiliary temple member 303 is pivoted to the lens frame 301. However, the torsion spring is small and low in spring force. Accordingly, when only one of the temples 306, 306a is unfolded, (e.g., the temple 306) and grasped by one hand to wear the spectacles, the angle xcex11 that each temple in relation to the plane of the lens frames 301 varies owing to the gravity acting on the lens frames 301 as shown in FIG. 8. Thus, the opposed temples 306a, 306 are out of balance with respect to the plane of the lens frames 301, so that the spectacles tilt as shown in FIG. 9 if worn in this state. The spectacles must then be worn again after correcting the unfolded state of the auxiliary temple members 303 with both hands.
An improved foldable spectacle frame is disclosed in U.S. Pat. No. 5,23 1,429 (see FIGS. 11A and 11B) and intends to solve the above problems, wherein the foldable spectacle frame is provided with a slide member 352 that engages with the lens frame 301 when the main temple member 304 is brought into an unfolded state and disengages from the lens frame 301 when the main temple member 304 is folded.
The above solution, however, has encountered difficulty in actual practice since sizes of projections 351 protruded from the slide members 352 and of the recessed portions formed on blocks 313 of the lens frames 301 are limited due to limited space available on the blocks 313. Hence, the projections 351 are liable to damages when users unintentionally or accidentally pivot the auxiliary temple members 303 prior to folding the main temple members 304.
The present invention provides a spectacle frame which is free of the above problems.
The present invention provides a foldable spectacle frame comprising two lens frames and two temples, wherein each temple comprises an auxiliary temple member being supported by a pivot provided at an outer portion of the lens frame and being movable about the pivot in an auxiliary plane of pivotal movement that is substantially orthogonal to the plane of the lens frame, and a main temple member pivoted to the auxiliary temple member rotatably in a main plane of pivotal movement that is orthogonal to the auxiliary plane of pivotal movement of the auxiliary temple member. The spectacle frame further comprises a slide member slidably provided within the auxiliary temple member and having a length permitting a base end thereof to project from the auxiliary temple member, and biasing means for biasing the slide member in a direction away from the pivot when folding the spectacle frame, wherein the pivot includes engaging means for engaging the slide member with the pivot by cooperation of the slide member, the pivot, and the main temple member. The slide member engages with the pivot when the main temple member is brought into an unfolded state and disengages from the pivot when the main temple member or the auxiliary temple member is folded.
The advantages and features of this invention can be easily comprehended by persons skilled in the art through the drawings and detailed explanations.